In an optical access network, the optical fiber link between a peripheral communication appliance of a network operator and an interface appliance of a user is typically the property of the network operator and is operated thereby.
The network operator guarantees its customers or the user a particular signal quality or transmission quality up to the user's interface.
In conventional systems, an additional interface appliance is therefore usually provided by the network operator at the location of the respective user, said additional interface appliance measuring the quality of the signal which is delivered to the user and which is adopted by the user. This additional interface appliance for ascertaining the signal quality for the user represents an additional outlay for the network operator, however. Furthermore, this interface terminal takes up additional space at the location of the user or customer. A further drawback is that the additional interface appliance consumes power for the signal quality measurement itself and hence the power consumption increases. In addition, the interface appliance provided for signal quality measurement requires separate maintenance.
It is therefore an object of the present invention to provide a method and an arrangement for measuring a power for an optical user signal transmitted via an optical fiber which have minimal power consumption.
The invention provides a method for measuring a power for an optical user signal transmitted via an optical fiber.
The invention provides a method for measuring a power for an optical user signal transmitted via an optical fiber, having the following steps:
(a) the transmitted optical user signal is converted (S1) into a pulsed optical measurement signal, the pulse repetition rate of which is dependent on the power of the transmitted optical user signal;
(b) the pulse repetition rate of the converted optical measurement signal is evaluated (S2) in order to ascertain the power of the optical user signal transmitted via the optical fiber.
In one embodiment of the method according to the invention, the optical user signal is transmitted via the optical fiber between a network operator transceiver of a network operator and a user transceiver of a user.
In one embodiment of the method according to the invention, the transmitted optical user signal is at least partially decoupled from the optical fiber at the user transceiver end by means of a power splitter for the purpose of measuring power.
In one embodiment of the method according to the invention, the converted, pulsed, optical measurement signal is launched into the optical fiber of the optical user signal to be transmitted or into a different optical fiber by means of a multiplexer and is supplied to a detection device situated at the network operator transceiver end for the purpose of evaluating the pulse repetition rate of the pulsed, optical measurement signal.
In one embodiment of the method according to the invention, the optical measurement signal has a different wavelength than the optical user signal.
In one embodiment of the method according to the invention, the pulse repetition rate of the pulsed, optical measurement signal is proportional to the power of the transmitted optical measurement signal.
The invention also provides a measurement arrangement for measuring a power for an optical user signal transmitted via an optical fiber.
The invention provides a measurement arrangement for measuring power for an optical user signal transmitted via an optical fiber, having:
(a) a signal conversion device for converting the optical user signal into a pulsed optical measurement signal, the pulse repetition rate of which is dependent on the power of the optical user signal; and having
(b) a detection device which evaluates the pulse repetition rate of the converted pulsed optical measurement signal in order to ascertain the power of the optical user signal transmitted via the optical fiber.
In one embodiment of the measurement arrangement according to the invention, a power splitter is provided which at least partially decouples the optical user signal transmitted on the optical fiber.
In one embodiment of the measurement arrangement according to the invention, a multiplexer is provided which loops back the optical measurement signal into the optical fiber of the optical user signal or launches it into a different optical fiber.
In one embodiment of the measurement arrangement according to the invention, the signal conversion device has:                a photodiode which converts the decoupled optical user signal into an electrical charging current,        a capacitor which is charged by the charging current until a threshold value voltage is reached, and        a nonlinear electronic circuit which connects the charged capacitor to a laser diode when the threshold value voltage is reached, said capacitor being discharged via the laser diode, which emits optical light pulses.        
In one embodiment of the measurement arrangement according to the invention, the signal conversion device and the detection device are provided at opposite ends of the optical fiber provided for the transmission of the optical user signal.
The invention also provides an optical fiber for transmitting an optical user signal.
The invention provides an optical fiber for transmitting an optical user signal, wherein at least one of the two ends of the optical fiber is provided with a signal conversion device which converts the optical user signal into a pulsed, optical measurement signal, the pulse repetition rate of which is dependent on the power of the transmitted optical user signal.
In one embodiment of the optical fiber according to the invention, the other end of the optical fiber is provided with a detection device which evaluates the pulse repetition rate of the converted, pulsed, optical measurement signal in order to ascertain the power of the optical user signal transmitted via the optical fiber.
In one embodiment of the optical fiber according to the invention, the optical fiber has a power splitter which at least partially decouples the optical user signal transmitted on the optical fiber to the signal conversion device.
In one embodiment of the optical fiber according to the invention, the optical fiber has a multiplexer which loops back the optical measurement signal into the optical fiber of the optical user signal or launches it into a different optical fiber.